Method for managing vehicle parking within a parking structure

ABSTRACT

One variation of a method for managing parking within a parking structure includes: after detecting a license plate number on a vehicle in an image captured by an entry camera unit arranged near an entry of the parking structure, labeling the license plate as unverified in a data log associated with the parking structure; in response to absence of validation of the license plate within a grace period after entry of the vehicle, relabeling the license plate as in-violation in the data log; in response to detecting the license plate in an image captured by a mobile enforcement unit moving through the parking structure, querying the data log for a status of the license plate; and, in response to the license plate labeled as in-violation in the data log, serving a prompt to an enforcement personnel to issue a citation to a vehicle carrying the license plate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a continuation of U.S. patent application Ser. No.16/735,206, filed on 6 Jan. 2020, which claims the benefit of U.S.Provisional Application No. 62/788,766, filed on 4 Jan. 2019, each ofwhich is incorporated in its entirety by this reference.

TECHNICAL FIELD

This invention relates generally to the field of vehicle parking systemsand more specifically to a new and useful method for managing vehicleparking within a parking structure in the field of vehicle parkingsystems.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a flowchart representation of a method;

FIGS. 2A-2D are flowchart representations of one variation of themethod; and

FIG. 3 is a flowchart representation of one variation of the method.

DESCRIPTION OF THE EMBODIMENTS

The following description of embodiments of the invention is notintended to limit the invention to these embodiments but rather toenable a person skilled in the art to make and use this invention.Variations, configurations, implementations, example implementations,and examples described herein are optional and are not exclusive to thevariations, configurations, implementations, example implementations,and examples they describe. The invention described herein can includeany and all permutations of these variations, configurations,implementations, example implementations, and examples.

1. Method

As shown in FIG. 1, a method S100 for managing vehicle parking within aparking structure includes: in response to detecting a license platenumber in a first image captured by an entry camera unit arranged nearan entrance of the parking structure, querying a whitelist for thelicense plate number in Block S110; and, in response to the whitelistcontaining the license plate number, billing a stored payment methodassociated with the license plate number for parking in the parkingstructure in Block S120 and appending a data log for the parkingstructure with the license plate number marked as validated (or “paid,”“verified”) in Block S122. The method S100 also includes, in response tothe whitelist excluding the license plate number: appending the data logfor the parking structure with the license plate number marked asunverified in Block S130; initiating a timer, associated with thelicense plate number, for a duration of a grace period in Block S132; inresponse to selection of the license plate number and submission of anew payment method at a kiosk in the parking structure, updating thelicense plate number as validated in the data log in Block S134; and, inresponse to expiration of the timer prior to authorization of thelicense plate number, updating the license plate number as in-violationin the data log in Block S136. The method S100 further includes: inresponse to detecting the license plate number in a second imagecaptured by a mobile enforcement unit associated with the enforcementpersonnel moving through the parking structure, querying the data logfor a status of the license plate number in Block S140; in response tothe data log returning an in-violation status of the license platenumber, serving a prompt to the enforcement personnel to issue acitation to a vehicle carrying the license plate number in Block S142;and, in response to detecting the license plate number in a third imagecaptured by an exit camera unit arranged near an exit of the parkingstructure, clearing the license plate number from the data log in BlockS150.

One variation of the method S100 shown in FIGS. 2A-2D includes, inresponse to detecting a first license plate number in a first imagecaptured by an entry camera unit arranged near an entrance of theparking structure, querying a whitelist for the first license platenumber in Block S110. This variation of the method S100 also includes,in response to the whitelist excluding the first license plate number:labeling the first license plate number as unverified in a data logassociated with the parking structure in Block S130; initiating a timer,associated with the first license plate number, for a duration of agrace period in Block S132; and, in response to expiration of the timerprior to validation of the first license plate number, relabeling thefirst license plate number as in-violation in the data log in BlockS136. This variation of the method S100 further includes: in response todetecting the first license plate number in a second image captured by amobile enforcement unit moving through the parking structure, queryingthe data log for a status of the first license plate number in BlockS140; in response to the first license plate number labeled asin-violation in the data log, serving a prompt to an enforcementpersonnel associated with the mobile enforcement unit to issue acitation to a first vehicle carrying the first license plate number inBlock S142; and, in response to detecting the first license plate numberin a third image captured by an exit camera unit arranged near an exitof the parking structure, labeling the first license plate number asexited in the data log in Block S150.

Another variation of the method S100 shown in FIGS. 2A-2D includes, inresponse to detecting a license plate number in a first image, capturedby an entry camera unit arranged near an entrance of the parkingstructure at a first time, querying a whitelist for the first licenseplate number in Block S110. This variation of the method S100 alsoincludes, in response to the whitelist excluding the first license platenumber: appending the data log for the parking structure with the firstlicense plate number labeled as unverified in Block S130; and, inresponse to absence of submission of a new payment method, inassociation with the first license plate number, at a physical kiosk inthe parking structure prior to a second time succeeding the first timeby a grace period duration, relabeling the first license plate number asin-violation in the data log in Block S136. This variation of the methodS100 further includes, in response to detecting the first license platenumber in a second image captured by a mobile enforcement unit movingthrough the parking structure and associated with an the enforcementpersonnel: querying the data log for a status of the first license platenumber in Block S140; and, in response to the first license plate numberlabeled as in-violation in the data log, serving a prompt to theenforcement personnel to issue a citation to a vehicle carrying thefirst license plate number in Block S142. Furthermore, this variation ofthe method S100 includes, in response to detecting the first licenseplate number in a third image captured by an exit camera unit arrangednear an exit of the parking structure at a third time, labeling thefirst license plate number as exited in the data log in Block S150.

Yet another variation of the method S100 shown in FIGS. 2A and 3includes: deploying a mobile enforcement unit to the parking structurein Block S160; accessing an image feed captured by a mobile cameraarranged on the mobile enforcement unit while the mobile enforcementunit moves past vehicles occupying parking spaces in the parkingstructure in Block S162; and scanning images, in the image feed, forlicense plate numbers in Block S164. This variation of the method S100also includes, for each license plate number detected in the image feed:querying a data log associated with the parking structure for a statusof the license plate number in Block S140; and, in response to thelicense plate number labeled as in-violation in the data log, outputtinga first notification—representing absence of parking validation for thelicense plate number within a grace period duration following entry ofthe vehicle into the parking structure—to an enforcement personneloccupying the mobile enforcement unit as the mobile enforcement unitmoves past a vehicle carrying the license plate number in Block S142;and queuing a printer to print a paper parking citation designating thelicense plate number in Block S144.

2. Applications

Generally, the method S100 can be executed by a system—including: anentry camera unit arranged near an entry of a parking structure, an exitcamera arranged near an exit of the parking structure, a kiosk locatedin or near the parking structure, and a mobile enforcement unit—toautomatically manage parking authorization and parking fees within theparking structure and to support the enforcement personnel operating inthe parking structure based on license plate numbers detected in imagescaptured by these entry, exit, and mobile enforcement units. Forexample, the system can be installed in a multi-level parking garage, aparking lot, or other parking structure to monitor license plate numbersof vehicles entering and exiting the parking structure, to collect andmanage payment methods provided by owners or operators of thesevehicles, and to interface with the enforcement personnel to issuecitations to unverified vehicles occupying the parking structure fordurations exceeding a grace period.

In particular, Blocks of the method S100 can be executed locally onentry and/or exit camera units arranged in the parking structure, akiosk arranged in or near the parking structure, a local computer systemarranged in the parking structure, and/or a remote computer system(e.g., a computer network, a remote server): to capture images of entryand exit lanes in the parking structure; to read license plate numbersof vehicles entering and exiting the parking structure; and to monitorvalidation (e.g., payment) status of vehicles carrying these licenseplate numbers. In one implementation, upon reading a license platenumber of a vehicle entering the parking structure—in an image capturedby the entry camera unit—the kiosk (or the local or remote computersystem) can: query a whitelist of license plate numbers linked to storedpayment methods; and query a pre-validation list of license platenumbers preemptively validated by local businesses or other localentities. Upon identifying the license plate number in the whitelist,the kiosk can initiate payment (or a “payment hold”) for a maximum dailyparking rate in the parking structure from a stored payment methodlinked to the license plate number; upon identifying the license platenumber (or a very similar license plate number) in the pre-validationlist, the kiosk can initiate payment—from a corresponding entity—for themaximum daily parking rate or for a maximum rate previously specified bythe corresponding entity. Upon confirmation of the payment hold, thekiosk can write the license plate number to a data log with thevehicle's time of entry (e.g., a timestamp of an image captured by theentry camera unit and depicting the license plate number) and a“validated” label.

However, if the kiosk (or the local or remote computer system) fails tofind the license plate number in the whitelist or pre-validation list,the kiosk can: write the license plate number to the data log with itstime of entry and an “unverified” label; and initiate a timer for agrace period duration (e.g., fifteen minutes) sufficient for thevehicle's operator to park the vehicle in a parking space in the parkingstructure, exit the vehicle, find a kiosk, and remit payment for parkingin the parking structure. During this grace period, the kiosk canpresent this license plate number on its integrated display, such asalong with other unverified license plate numbers of other vehicles thatrecently entered the parking structure. Upon selection of this licenseplate number and submission of a payment method (e.g., a credit card) atthe kiosk, the kiosk (or the local or remote computer system) can:initiate payment for the maximum daily parking rate from the suppliedpayment method; and update the data log to reflect validation of thelicense plate number.

In the foregoing scenarios, when the kiosk (or exit camera unit, localcomputer system, or remote computer system) detects the license platenumber in an exit image captured by the exit camera unit, the kiosk can:calculate a total duration of time from entry of the vehicle into theparking structure to exit of the vehicle from the parking structure(such as less the grace period duration); calculate a parking fee forthis total duration; and then initiate a partial refund—to the paymentmethod supplied for the license plate number—for the difference betweenthe maximum daily rate and the parking fee if the maximum daily rateexceeds the parking fee.

However, if the grace period timer for this license plate number expiresprior to submission of a valid payment method linked to this licenseplate number, the kiosk (or the local or remote computer system) canupdate the data log to reflect that the license plate number is now inviolation of parking and payment rules of the parking structure.

The kiosk (or the local or remote computer system) can execute theforegoing process for each vehicle entering and exiting the parkingstructure.

Concurrently, an enforcement personnel may navigate an enforcementvehicle—such as a low-speed vehicle or a golf cart outfitted with amobile enforcement unit—throughout the parking structure. The mobileenforcement unit can include a camera facing outwardly from a side ofthe enforcement vehicle such that license plate numbers arranged onvehicles parked in parking spaces in the parking structure fall withinthe field of view of this camera as the enforcement personnel drives theenforcement vehicle through the parking structure. In particular, themobile enforcement unit can: capture images as the enforcement personneldrives the enforcement vehicle through the parking structure; implementmethods and techniques similar to the entry and exit camera units todetect and read license plate numbers from these images in nearreal-time; and can query the data log for a status of each license platenumber read from these images. In response to the data log returning an“in-violation” status of a license plate number thus read from an imagecaptured by the mobile enforcement unit, the mobile enforcement unit canoutput a notification to the enforcement personnel, such as in the formof: an audible prompt; and/or a prompt—rendered on a display coupled tothe mobile enforcement unit—identifying the license plate number andincluding a prompt to issue a citation to a nearby vehicle carrying thislicense plate number. Upon receipt of confirmation from the enforcementpersonnel to issue a citation to this vehicle, the mobile enforcementunit can automatically generate a digital copy of a citation for thisvehicle—such as including the license plate number, the entry time ofthe vehicle retrieved from the data log, an identifier of the parkingstructure, and the current time—and then queue a printer coupled to themobile enforcement unit to print this citation. The enforcementpersonnel may then place this printed citation on the correspondingvehicle.

Therefore, Blocks of the method S100 can be executed by and/or incooperation with a kiosk, entry and exit camera units, and a mobileenforcement unit to monitor payment statuses of vehicles occupying theparking structure and to enforce parking rules in the parking structurewithout necessitating installation of gates, underground vehiclesensors, or other substantive infrastructure. The system can thereforebe rapidly deployed to a parking structure with limited infrastructurechanges or investment. Furthermore, by averting gates, undergroundvehicle sensors, or other substantive infrastructure, the system canconsistently and reliably execute the method S100 over time with limitedmaintenance or management of physical systems (e.g., repair of gates,replacement of battery-powered vehicle sensors).

By automatically detecting license plate numbers entering the parkingstructure, monitoring statuses of these license plate numbers based onpayment rules assigned to the parking structure, and automaticallydetecting license plate numbers in images captured by the mobileenforcement unit as the enforcement personnel navigates the enforcementvehicle and mobile enforcement unit throughout the parking structure,the system—executing Blocks of the method S100—can retrieve statuses ofvehicles in the immediate vicinity of the enforcement personnel in(near) real-time and selectively prompt the enforcement personnel tostop the enforcement vehicle and issue citations to in-violationvehicles only, thereby enabling the enforcement personnel to rapidlyscan vehicles in the parking structure with minimal downtime.Furthermore, by automatically generating citations for in-violationvehicles based on their entry times and license plate numbers andinterfacing with a printer to automatically print citations forin-violation vehicles according to the method S100, the system canenable the enforcement personnel to quickly retrieve and place acitation on an in-violation vehicle within minimal manual input beforereturning to navigating the enforcement vehicle through the parkingstructure. For example, the system can execute Blocks of the method S100to enable the enforcement personnel to scan up to 4,000 vehicles perhour while navigating the enforcement vehicle at a speed of 10 miles perhour within a parking structure with rows of ten-foot-wide parkingspaces. In another example, the system can execute Blocks of the methodS100 to enable the enforcement personnel to scan every parking space ina 400-stall parking structure and place citations on four in-violationvehicles in the parking structure within ten minutes.

Furthermore, because the method S100 enables such time-efficient andpersonnel-efficient monitoring of vehicles entering a parking structure,the system can be deployed to a cluster of parking structures and thesystem can interface with a single mobile enforcement unit mounted on asingle enforcement vehicle operated by a single enforcement personnel tomonitor vehicles in the parking structures. For example, the system canbe deployed to a cluster of four parking structures located on one cityblock and containing a total of 2,000 parking spaces; and theenforcement personnel—operating the single enforcement vehicle with thesingle mobile enforcement unit at a speed of ten miles per hour withinthese parking structures and at a speed of twenty miles per hour betweenparking structures—can scan every parking structure in each of theseparking structures and issue citations to all in-violation vehicles atleast once per hour.

Therefore, the Blocks of the method S100 can be executed by the systemto achieve efficient and simple management of a large number of parkingspaces such as across multiple parking structures—by a small number of(e.g., a single) enforcement personnel.

3. System

As described above and shown in FIG. 1, the method S100 can be executedby a system including: an entry camera unit arranged near an entry of aparking structure; an exit camera arranged near an exit of the parkingstructure; a kiosk located in or near the parking structure; and amobile enforcement unit.

3.1 Camera Units

In particular, the system can include a forward-facing entry camera unitconfigured for arrangement near a vehicle entrance of the parkingstructure such an entry lane of the parking structure falls within afield of view of an entry camera (e.g., a black-and-white, grayscale, orcolor camera) arranged in the forward-facing entry camera unit. Frontsof vehicles entering the parking structure—and front-mounted licenseplates arranged on these vehicles—may therefore fall into the field ofview of the entry camera. The forward-facing entry camera unit can alsoinclude a motion sensor defining a field of view that intersects thefield of view of the entry camera. As described below, theforward-facing entry camera unit can thus capture images when the motionsensor detects motion in its field of view. Alternatively, the entrycamera in the forward-facing entry camera unit can capture imagescontinuously while in operation.

The system can similarly include a forward-facing exit camera unitconfigured for arrangement near a vehicle exit of the parking structuresuch that an exit lane of the parking structure falls within a field ofview of an exit camera arranged in the forward-facing exit camera unit.Fronts of vehicles exiting the parking structure—and front-mountedlicense plates arranged on these vehicles—may therefore fall into thefield of view of the exit camera. Like the forward-facing entry cameraunit, the forward-facing exit camera unit can also include a motionsensor defining a field of view that intersects the field of view of theexit camera.

In one variation, the system additionally or alternatively includes arear-facing entry camera unit configured for arrangement near a vehicleentrance of the parking structure such that an entry lane of the parkingstructure falls within a field of view of an entry camera arranged inthe rear-facing entry camera unit. Rears of vehicles entering theparking structure—and rear-mounted license plates arranged on thesevehicles—may therefore fall in the field of view of this entry camera.In this variation, a forward-facing entry camera unit and a rear-facingentry camera unit can be paired and face opposing directions near avehicle entrance of the parking structure and can cooperate to captureimages of both the front and rear license plates of each vehicleentering the parking structure, thereby increasing a quantity of dataavailable to the system to identify each vehicle entering the parkingstructure and thus increasing probability that the system willaccurately read at least one license plate on each vehicle entering theparking structure.

Similarly, the system can additionally or alternatively include arear-facing exit camera unit configured for arrangement near a vehicleexit of the parking structure such that an exit lane of the parkingstructure falls within a field of view of an exit camera arranged in therear-facing exit camera unit. Rears of vehicles exiting the parkingstructure—and rear-mounted license plates arranged on these vehicles—maytherefore fall into the field of view of this exit camera. In thisvariation, a forward-facing exit camera unit and a rear-facing exitcamera unit can be paired and face opposing directions near a vehicleexit of the parking structure and can cooperate to capture images ofboth the front and rear license plates of each vehicle exiting theparking structure, thereby increasing a quantity of data available tothe system to identify each vehicle exiting the parking structure andthus increasing probability that the system will accurately read atleast one license plate on each vehicle exiting the parking structure.

Furthermore, for a parking structure containing multiple entries and/ormultiple exits, the system can include: one entry camera unit (orforward-facing and rear-facing entry camera unit pair) per entry; andone forward-facing exit camera unit (or forward-facing and rear-facingexit camera unit pair) per exit.

3.2 Kiosk

The system also includes a kiosk configured to installation within theparking structure, such as: near a pedestrian exit on a first level of amulti-level parking garage; near pedestrian exits and stairwells on eachlevel of a multi-level parking garage; or near a pedestrian exit in aparking lot.

The kiosk can include: a payment reader; a user interface, such asincluding a display, touchscreen, and/or keypad; a communication module;and a processor. The payment reader can include a credit card readerconfigured to collect payment information from a credit card or debitcard and/or a wireless payment reader configured to read paymentinformation from a mobile device supplied by a user. The communicationmodule: can support communications with a remote computer system (e.g.,a remote server, a payment processor) over a cellular network or wiredlocal area network; can support wired or wireless communications withentry and exit camera units installed in the parking structure toreceive images captured by these camera units and/or license platenumbers detected by the camera units; and can support wirelesscommunications with an enforcement unit, such as including license platenumber statuses and issuance of citations. The processor is configuredto detect and extract license plate numbers of vehicles entering andexiting the parking structure from images received from entry and exitcamera units via the communication module, as described below.

Alternatively, the entry camera unit can include an integrated processorconfigured to detect and extract license plate numbers from imagescaptured by a camera in the entry camera unit in (near) real-time; and acommunication module can transmit this license plate number back to thekiosk for further handling. The exit camera unit: can similarly includea processor configured to locally process images captured by a camera inthe exit camera unit; and can similarly return license plate numbersextracted from these images to the kiosk in (near) real-time.

Yet alternatively, the entry and exit camera unit can return images tothe kiosk in (near) real-time, the kiosk can transmit these images(e.g., via a wired or wireless connection) to an external computersystem, and the external computer system (e.g., a remote server, a localcomputer arrange in the parking structure) can detect and extractlicense plate numbers—of vehicles entering and exiting the parkingstructure—from these images.

4. Vehicle Detection

Therefore, a processor in each entry and exit camera unit, a processorin the kiosk, or a external computer system can process images capturedby these entry and exit camera units to track vehicles entering andexiting the parking structure.

4.1 Plate Detection with Motion Sensing

In one implementation, the entry camera unit defaults to operating in aninactive state. When the motion sensor in the entry camera unit detectsmotion in its field of view—and therefore in the field of view of thecamera—the entry camera unit enters an active state. In the activestate, the camera records a sequence of timestamped images (e.g.,black-and-white, grayscale, or RGB color images), such as at a rate of 2Hz. When the motion sensor no longer detects motion in its field ofview, the entry camera unit returns to the inactive state. The entrycamera unit serves these timestamped images to the kiosk over a wired orwireless connection, such as in real-time as these images are capturedor en masse prior to returning to the inactive state.

The processor—in the kiosk—then locally scans this set of timestampedimages received from the entry camera unit for a license plate number ofa vehicle. In one example, the processor: implements computer visiontechniques—such as edge detection, object detection, and/or opticalcharacter recognition, etc.—to scan each image in this sequence for alicense plate number; and calculates a confidence score for a licenseplate number detected in each of these images, such as based on afrequency that the same license plate number is detected in other imagesin this set, blurriness of the image, etc. The processor can then: storea license plate number—read from this set of images—associated with ahighest confidence score in the set in order to uniquely identify thisvehicle; and pair this license plate number with an entry time, such asa time (and date) that a first image—depicting this license platenumber—in the set of images was captured by the entry camera unit.

4.2 Voting

In another implementation, the entry camera unit streams images to theremote computer system, such as at a rate of 10 Hz. Upon receipt of anext image from the entry camera unit, the remote computer systemcompares this next image to a preceding image (or to a baseline image)and saves this next image to an image folder in a database in responseto the difference between this next image and the preceding (orbaseline) image exceeding a threshold difference. Then, when time sincea last image was saved to this folder exceeds a threshold duration(e.g., two seconds, which may correspond a time for a vehicle enteringthe parking structure to pass the entry camera unit), the, the remotecomputer system can initiate a processing cycle to extract a licenseplate number from images in this folder.

During this processing cycle, the remote computer system can implementoptical character recognition and/or other computer vision techniques tointerpret a set of (e.g., four) most-likely license plate numbers and torank these license plate numbers in order of confidence for each imagein this folder. For example, the remote computer system can extract atotal of 200 license plate number predictions over 50 images captured bythe entry camera unit over a period of five seconds as a vehicle entersthe parking structure, with each license plate number in this set ranked“1” (i.e., for lowest confidence in the set), “2,” “3,” or “4” (i.e.,for highest confidence in the set). The remote computer system then sumsthe rank values within each unique group of identical license platenumbers in this set and store each of these sums as a score for itscorresponding license plate number. The remote computer system can alsocompare each of these unique license plate numbers to license platenumbers previously detected in this parking structure and increases thescore for each unique license plate number matched to a license platenumber previously detected in this parking structure.

The remote computer system can then: store the license plate number—fromthis set of license plate numbers read from this set of images in theimage folder—associated with the highest score; pair this license platenumber with an entry time, such as a time (and date) of a first image—inthe folder—in which this license plate number was detected; and thendiscard this image folder.

4.3 Representative Image

The processor can also select and store a representative image of thisvehicle. For example, the processor can identify a least-blurry image—inthe set of images—in which the license plate number is detected in thebottom half of the image and store this image as a representative imageof the vehicle uniquely identified by this license plate number.

4.4 Multiple Vehicles

Furthermore, if two or more vehicles entered the parking structure overa period of time that this set of images was captured, the processor canimplement similar methods and techniques to: detect multiple uniquelicense plate numbers in this set of images; isolate contiguoussequences of images depicting the same (or similar) license platenumbers; store a license plate number associated with a highestconfidence score for each contiguous sequence of images that depict thesame or similar license plate numbers; and associate each of theselicense plate numbers with an entry time based on timestamps ofimages—in this set of images—depicting these license plate numbers. Theprocessor can therefore: detect, identify, and distinguish a sequence ofvehicles that entered the parking structure near the entry camera unitin this set of images; store each of these license plate numbers with anentry time (and entry date) that the corresponding vehicle thus enteredthe parking structure; and select and store a representative image ofeach of these vehicles.

4.5 Local V. Remote Processing

Alternatively, upon receipt of this set of images from the entry cameraunit, the kiosk can transmit this set of images to the external computersystem, or the entry camera unit can transmit this set of imagesdirectly to the external computer system. The external computer systemcan implement similar methods and techniques to detect and extract alicense plate number and entry time of a vehicle from these images.

Yet alternatively, the entry camera unit can: locally process this setof images to identify a license plate number of a vehicle and entry timeof a vehicle; select a representative image of the vehicle from this setof images; and return this license plate number and entry time to thekiosk, such as over a wired or wireless connection.

4.6 Multiple Cameras

In the variation described above in which the system includes both aforward-facing entry camera unit and a rear-facing entry camera unitfacing the same entry in the parking structure, the kiosk (or the remotecomputer system) can verify a license plate number of a vehicle enteringthe parking structure based on alignment between license plate numbersdetected in a first set of images captured by the forward-facing entrycamera unit and detected in a second set of images captured by therear-facing entry camera unit soon after the first set of images.

The system can execute the foregoing methods and techniques for eachentry camera unit installed in the parking structure in order to detectand store license plate numbers, entry times, and representative imagesof vehicles entering the parking structure. The system can implementsimilar methods and techniques for each exit camera unit installed inthe parking structure in order to detect license plate numbers and exittimes of vehicles exiting the parking structure.

However, the system can implement any other method or technique to:detect a license plate number of a vehicle entering the parkingstructure; store an entry time of the vehicle identified by this licenseplate number; detect the license plate number of the vehicle laterexiting the parking structure; and store an exit time of the vehicleidentified by this license plate number. Furthermore, license platenumber detection in images captured by an entry or exit camera unit canbe executed in any other way locally on the camera unit, locally at thekiosk, and/or remotely by the external computer system, such as toaccommodate wireless network bandwidth limitations and/or localprocessing limitations.

5. Data Log

In the foregoing implementations, the system can store a license platenumber and entry time of a vehicle thus detected in a set of imagescaptured by an entry camera unit in a data log (or table, database, orother file). For example, the kiosk—installed in the parkingstructure—can store a local copy of the data log in local memory.Additionally or alternatively, the remote computer system can store aremote copy of the data log, such as a remote master copy of the datalog.

6. Whitelist and Validated Vehicle

Block S110 of the method S100 recites, in response to detecting alicense plate number in an image captured by the entry camera unit,querying the whitelist for the license plate number. Blocks S120 andS122 of the method S100 recite, in response to the whitelist containingthe license plate number: initiating payment for parking in the parkingstructure via a stored payment method associated with the second licenseplate number; and labeling the second license plate number as validatedin the data log, respectively.

Generally, once the system identifies a license plate number and entrytime of a vehicle that recently entered the parking structure, thesystem can query a whitelist—associated with the parking structure—withthe license plate number in order verify whether the license platenumber corresponds to a current parking permit for the parking structureor is associated with stored payment information, as shown in FIGS. 1and 2.

In one implementation, after detecting entry of a new vehicle in a setof images recently captured by an entry camera unit installed in theparking structure, the system (e.g., the kiosk or the remote computersystem) queries a “whitelist” of license plate numbers of vehicles—forwhich parking passes are current and for which a payment method waspreviously supplied—for the license plate number of this new vehicle. Ifthe whitelist returns confirmation that the license plate number isassociated with a current parking pass for which payment was previouslysupplied (e.g., a monthly parking pass specifying unlimited parking inthe parking structure for a one-time upfront fee that was already paidfor by the owner of the vehicle associated with the license platenumber), the system can label (or “tag”) the license plate number asvalidated in the data log.

Similarly, if the whitelist returns confirmation that the license platenumber is associated with a current parking pass for which a paymentmethod (e.g., a credit card, a deposit account) was previously suppliedbut that is billed ad hoc when the vehicle's license plate number isdetected in the parking structure, the system can: initiate payment—viathe supplied payment method—for a maximum daily parking fee for parkingin the parking structure; and then tag the license plate number asvalidated in the data log when payment with the supplied payment methodis confirmed.

Similarly, if the whitelist returns confirmation that the license platenumber is associated with a payment method that was previouslysupplied—such as when the vehicle was previously parked in the sameparking structure or in a related parking structure though the licenseplate number is not necessarily affiliated with a parking pass for theparking structure—the system can: initiate payment via the paymentmethod associated with the license plate number for a maximum dailyparking fee for parking in the parking structure; and then tag thelicense plate number as validated in the data log when payment with thesupplied payment method is confirmed.

6.1 Whitelist Setup

In one implementation, to add a license plate number of a vehicle to thewhitelist, a user may submit an application form in paper, via email, oronline (e.g., within a web browser or native application). For example,the user may: supply a license plate number; supply a payment method(e.g., credit card information, debit card information, or bank transferinformation for a parking deposit account); specify a particular parkingstructure, parking structure complex, parking structure network, orlocation (e.g., an office park, a city block); start and end dates;and/or contact information (e.g., an email address, a phone number) inthe application. The system (e.g., the remote computer system) or arepresentative of this system can then create a user account that linksthe supplied license plate number and payment method to one or moreparking structures outfitted with a kiosk, entry camera unit, and exitcamera unit. Later, the system can automatically bill the suppliedpayment method when this license plate number is detected in an imagecaptured by an entry camera unit in one of these parking structures, asdescribed above.

Therefore, the system can link a license plate number on a vehicle to apayment method (e.g., credit card information) supplied by the vehicle'sowner or operator. The system can also link owner or operator contactinformation to the license plate number of the vehicle and canautomatically return a parking receipt (e.g., via email) to thevehicle's owner or operator—for actual time spent in a parkingstructure—when the vehicle's license plate number is detected in theparking structure, thereby: simplifying a physical kiosk in the parkingstructure (e.g., by eliminating a paper receipt printer); and reducingneed of the owner or operator to visit the kiosk upon entry into or exitfrom the parking structure, which may enable fewer kiosks to serve moreparking spaces in a parking structure.

7. Grace Period and Unverified Vehicle

Blocks S130 and S132 recite, in response to the whitelist excluding thelicense plate number: labeling the license plate number as unverified inthe data log associated with the parking structure in Block S130; andinitiating a timer, associated with the license plate number, for theduration of the grace period, respectively.

Generally, if the whitelist returns lack of association between thelicense plate number and a current parking pass or stored paymentmethod, the system can: mark the license plate number as “in graceperiod” in the data log; and initiate a timer linked to this licenseplate number for a grace period, as shown in FIG. 2A. For example, thesystem can implement a fixed grace period duration of fifteen minutes,which may be sufficient time for a vehicle operator to enter the parkingstructure, find a parking space, park her vehicle, walk to a kiosk,select her license plate number, and enter payment for parking in theparking structure. Alternatively, the system can dynamically adjust thegrace period duration, such as inversely proportional to a totalquantity of unoccupied spaces remaining in the parking structure (e.g.,as calculated based on a total quantity of parking spaces in thefacility, less a total quantity of vehicles that have entered theparking structure, plus a total quantity of vehicles that have exitedthe parking structure). The system can also implement different graceperiod durations in different parking structures, such as based on(e.g., proportional to) a maximum distance from a parking space to anearest kiosk in a parking structure.

In one variation, if the whitelist returns confirmation that the licenseplate number is associated with user contact information (e.g., an emailaddress, a phone number) and a supplied payment method but the paymentmethod is rejected after one or more billing attempts by the system, thesystem can serve a prompt to update payment information via the suppliedcontact information, such as in the form of an email, a SMS textmessage, or a robo-call. If the payment method linked to the licenseplate number did not previously fail (e.g., if the payment method onlyrecently expired), the system can also mark the license plate number as“in grace period” in the data log for the remainder of the current day,thereby granting a user affiliated with the vehicle an opportunity tosupply updated payment information when convenient, such as through thekiosk, a web portal, or a native application, as described below.However, if the payment method linked to the license plate number didfail on a previous day in which the vehicle entered the parkingstructure and if a user affiliated with the vehicle failed to supplyupdated payment information before reentering the parking structure onthe current day, the system can: mark the license plate number as “ingrace period” in the data log; and initiate a timer linked to thislicense plate number for the grace period (e.g., fifteen minutes).

7.1 Grace Period Payment

Block S134 of the method S100 recites, in response to receivingidentification of the license plate number and submission of a paymentmethod through a physical kiosk associated with the parking structureprior to expiration of the timer: relabeling the license plate number asvalidated in the data log; and initiating a payment hold, for a maximumdaily parking rate in the parking structure, from the payment method.Generally, in Block S134, the system can receive selection of anunverified license plate number and submission of a payment method viathe kiosk, initiate payment for parking in the parking structure by avehicle carrying this license plate number, and update the data log toreflect a validated status of this license plate number, as shown inFIG. 2B.

In one example, after driving into the parking structure, a user parksher vehicle inside the parking structure. If the user does not have acurrent parking pass for the parking structure or has not previouslysupplied a payment method for parking in the parking structure, the userwalks to the kiosk to supply payment information.

In one implementation, the kiosk renders a prompt—on its display—toenter a license plate number, such as through a touchscreen or keypad.Upon arriving at the kiosk, the user manually enters the license platenumber on her vehicle, and the system (e.g., the kiosk or the remotecomputer system) then queries the data log for the supplied licenseplate number. If the data log returns confirmation that the licenseplate number is contained in the data log (i.e., the license platenumber supplied by the user matches a license plate number recentlydetected in an image captured by an entry camera unit installed in theparking structure), the kiosk can then prompt the user to supplypayment, such as by dipping a credit card or debit card into a cardreader in the kiosk. The system then: charges a maximum daily parkingrate (or maximum daily parking rate for the remainder of the currentday) to the supplied payment method; and updates the data log to reflectthat the license plate number is now validated once payment from thesupplied payment method is confirmed.

In the foregoing implementation, as the user enters a string ofalphanumeric characters for the license plate number of her vehicle intothe kiosk, the kiosk can: query the data log for license plate numberswith the same string of characters; render the set of license platenumbers returned by the data log on the display; and prompt the user toeither enter the license plate number in its entirety or select from theset of license plate numbers rendered on the display. The kiosk cansimilarly: query the data log for license plate numbers with both thesame and similar—but not identical—string of characters entered by theuser; render this set of license plate numbers returned by the data logon the display; and prompt the user to either enter the license platenumber in its entirety or select from the set of license plate numbersrendered on the display.

Additionally or alternatively, the kiosk can: render license platenumbers—of vehicles that recently entered the parking structure and forwhich payment has not yet been received—on the display; prompt the userto filter this set of license plate numbers by entering characters thatshe knows are included in her vehicle's license plate number; and thenenable the user to select from this filtered list of license platenumbers. For example, the kiosk can: aggregate a list of license platenumbers labeled as unverified in the data log (i.e., license platenumbers of vehicles that recently entered the garage but for whichpayment or validation by an external entity has not yet been received);order license plate numbers in this list according to their entry times(e.g., according to timestamps of images captured by the entry cameraand depicting these license plate numbers); and render this ordered listof license plate numbers on its integrated display. In this example, thekiosk can render these license plate numbers: in a grid array, such aswith the license plate number detected most recently in a top-leftcorner of the display; in a vertical list with most-recent license platenumber at a top of the list; or in a vertical or horizontal scrollingbar with the most-recent license plate number displayed first. Thephysical kiosk can then: receive selection of a license plate numberfrom this ordered list of license plate numbers rendered on the display;receive submission of a payment method associated with the selectedlicense plate number; initiate payment for parking in the parkingstructure—by a vehicle carrying the selected license plate number—viathe supplied payment method in Block S120; and re-label this licenseplate number as “validated” in the data log in Block S122. The systemcan thus enable the user to identify her vehicle's license plate numbereven if she does not remember this license plate number in its entirety.

Similarly, the kiosk can: retrieve representative images (describedabove) of vehicles that recently entered the parking structure and forwhich payment has not yet been received; render these representativeimages on the display; prompt the user to select the representativeimage that depicts her vehicle; and prompt the user to supply a paymentmethod. For example, the kiosk can: query the data log for a set oflicense plate numbers that have not yet been validated; retrieve a setof representative images, each associated with one license plate numberin this set of unverified license plate numbers; render this set ofrepresentative images on the display, such as in chronological orderwith the most-recent representative image depicted at a top of thedisplay; and enable the user to scroll through this set ofrepresentative images to find an particular representative image inwhich the user recognizes her vehicle. The system can then associate apayment method supplied by the user with the license plate number linkedto (e.g., depicted in) the representative image selected by the user.

Furthermore, in the foregoing implementations, the kiosk can update thelist of unverified license plate numbers in real-time as license platenumbers are detected in images captured by the entry camera unit or inresponse to activation of the kiosk by a user (e.g., by touching thedisplay).

In the foregoing implementations, the kiosk can also: present bothunverified and in-violation license plate numbers on the display; enablea user to select and remit payment for unverified license plate numbers;and enable a user to select and remit payment for citations issued to anin-violated license plate number, such as if fewer than a thresholdquantity of parking citations are outstanding for this license platenumber as described below.

7.2 Stored Payment

In one variation as shown in FIG. 2B, the kiosk can also prompt the userto enter contact information in order to receive an electronic receipt,such as a phone number or email address. The kiosk can also prompt theuser to elect to store the supplied payment method—linked to the licenseplate number—for payment for future parking in the parking structure(and in affiliated parking structures) with the same vehicle. If theuser thus supplies contact information and elects to store the suppliedpayment method, the system (e.g., the kiosk or remote computer system)can: generate a new user profile including the license plate number,user contact information, and payment method; and add this license platenumber to the whitelist.

For example, in response to detecting a license plate number in an imagecaptured by the entry camera unit at a first time, the system can querythe whitelist for this license plate number in Block S110. In responseto the whitelist excluding this license plate number, the system canlabel this license plate number as unverified in the data log in BlockS130. The kiosk can then: aggregate a list of license plate numberslabeled as unverified in the data log; present this list of licenseplate numbers (e.g., on its integrated display); receive selection ofthe license plate number—by a user—from this list of license platenumbers; receive submission of a payment method—associated with thislicense plate number—from the user; initiate payment with the suppliedpayment method; and update the license plate number as “validated” inthe data log. The kiosk can also prompt the user to confirm a persistentlink between this supplied payment method and this license plate numberin order to automate payment for future parking—with a vehicle carryingthis license plate number—in the parking structure. Then, in response tothe user confirming this persistent link between the supplied paymentmethod and the selected license plate number for future parking in theparking structure, the system can: store the supplied payment method inassociation with this license plate number; and add the license platenumber to the whitelist for the parking structure.

8. Pre-Validation

In one variation shown in FIG. 2A, the method S100 further includes: inresponse to detecting a license plate number in an image captured by theentry camera unit, querying a pre-validation list—containing licenseplate numbers designated in pre-validation requests submitted by anexternal entity—for the license plate number in Block S112; and, inresponse to the pre-validation list containing the license plate number,labeling the license plate number as validated in the data log in BlockS122.

Generally, in this variation, the system supports parking authorizationby an external entity (or an external “institution”) for vehicles parkedin the parking structure. In one example, a user: parks her vehicle inthe parking structure; exits the parking structure on foot; enters aninstitution (e.g., a bank, a restaurant, and store) nearby; and providesher license plate number to a representative of the institution. Therepresentative then enters the license plate number provided by the userinto an email (e.g., into a subject heading in the email) and sends thisemail to an email address monitored by the remote computer system. Thesystem then: identifies the institution based on a domain of a sender ofthe email; identifies a particular parking structure (or a set ofparking structures) for which parking authorization has been enabled forthe institution; extracts the license plate number from the email; andqueries a data log associated with the particular parking structure forthe license plate number to confirm that a vehicle with this licenseplate number recently entered the parking structure. (If multipleparking structures are affiliated with the institution, the systemsimilarly can query data logs for each of these parking structures bothto confirm that a vehicle with this license plate number recentlyentered one of these parking structures and to identify the particularparking structure occupied by vehicle.) If the data log returns a “true”value for this license plate number, the system can: retrieve a storedpayment method affiliated with the institution; charge the institution'sstored payment method for a maximum daily parking fee for parking forthe parking structure; and update the data log for the parking structureto indicate the license plate number as validated once payment with theinstitution's payment method is confirmed.

(In this variation, the representative of the institution may entermultiple license plate numbers into the subject line of the email, andthe system can then: extract each of these license plate numbers; andexecute the foregoing methods and techniques to validate parking foreach of these vehicles.)

However, the system can receive and handle electronic communications ofany other form or type—such as a form entered via a web browser or arequest entered via a native application executing on a computing deviceassociated with a representative of the external institution—to validateparking in the parking structure on behalf of the user.

8.1 Pre-validation Time Limit

In this variation, the system can also implement a maximum parkingauthorization time that the institution agrees to pay on behalf of theuser. For example, the system can implement a fixed maximum parkingauthorization time, such as previously specified by the institution(e.g., two hours for a restaurant, thirty minutes for a bank).Alternatively, the system can apply a maximum parking authorization timespecified in the authorization email sent by the representative of theinstitution. For example, the representative may enter both the licenseplate number supplied by the user and a maximum parking authorizationtime (e.g., a number of minutes contained in closed brackets) into thesubject line of the email; and the system can extract this maximumparking authorization time from the email upon receipt. The system canthen charge the institution's payment method for a cost of the fixed orcustom maximum parking authorization time. Later, if the system detectsthat a vehicle with this license plate number left the parking structurebefore conclusion of the maximum parking authorization time set for orspecified by the institution, the system can refund the institution fora difference in cost between this maximum parking authorization time andthe actual duration of time that the vehicle with this license platenumber occupied the parking structure. If the user also supplied paymentfor parking in the parking structure—such as via the kiosk when sheinitially parked in the parking structure, as described above—the systemcan also issue a full refund to the user.

However, if the system fails to detect a vehicle with this license platenumber leaving the parking structure before conclusion of the maximumparking authorization time and the user previously supplied payment forparking in the parking structure, the system can: transition to chargingthe user's supplied payment method for time that her vehicle remains inthe parking structure beyond the maximum parking authorization time setfor or specified by the institution; and preserve a “validated” labelfor the license plate number in the data log. Conversely, if the systemfails to detect a vehicle with this license plate number leaving theparking structure before conclusion of the maximum parking authorizationtime set for or specified by the institution but the user did notpreviously supply payment for parking in the parking structure, thesystem can update the data log to indicate that the license plate numberis in-violation (or “unauthorized”), such as after an additional graceperiod of fifteen minutes.

For example and as shown in FIGS. 2A and 2C, the system can: query apre-validation list for a license plate number detected in an imagerecently captured by the entry camera unit; label this license platenumber as validated in the data log if the pre-validation list containsthis license plate number; and initiate a validation timer for a maximumvalidation duration specified by the external entity (e.g., one hour fora fast food restaurant; two hours for a casual dining restaurant; fourhours for a fine dining restaurant). Later, if the system detects thislicense plate number in an image captured by the exit camera (i.e., ifthe system determines that this vehicle has left the parking structure)prior to expiration of the validation timer, the system can: initiatepayment from the external entity on behalf of the vehicle for theduration of time that the vehicle occupied the parking structure; andupdate the data log to reflect the vehicle's exit from the parkingstructure. Conversely, if the system fails to detect this license platenumber in an image captured by the exit camera (i.e., if the systemdetermine that this vehicle has not yet left the parking structure) andif an alternate payment method has not yet been supplied for or linkedto this license plate number prior to expiration of the validationtimer, the system can: initiate payment from the external entity onbehalf of the vehicle for the maximum validation duration specified bythe external entity; and re-label the license plate number as unverifiedin the data log.

8.2 Repeat Authorization

In one variation, the system maintains a validation log of license platenumbers validated (or “authorized”) by the institution. For example, thesystem can append the authorization log with a license plate numberresponsive to an email or other electronic communication from arepresentative of the institution requesting authorization of thelicense plate number, as described above.

When the system detects a license plate number on a vehicle entering theparking structure as described above, the system can query theauthorization log for this license plate number. If the authorizationlog returns a “true” value, the system can automatically transmit anelectronic communication (e.g., an email)—to a representative of theinstitution—that: indicates a user for whom the institution previouslyvalidated parking has returned to the parking structure; and prompts therepresentative to re-validate parking on behalf of the user. In thisexample, the system can also: incorporate a representative images of theuser's vehicle (e.g., a low-blur image captured by an entry camera unitwhen the vehicle entered the parking structure) into the electroniccommunication; and/or incorporate a name of the user (e.g., extractedfrom a payment method supplied by the user and thus linked to thislicense plate number) into the electronic communication in order toenable the representative of the institution to identify the user. Therepresentative may then reply to the electronic communication (e.g., byreplying to the email or replying to the email with a “YES” added to thesubject line) in order to trigger the system to validate parking for theuser with a payment method supplied by the institution, as describedabove. In this implementation, the representative may also preparepaperwork, prepare refreshments, prepare a conference room, and/ornotify associates, etc. of the user's pending arrival responsive to thiselectronic communication received from the system.

9. “In-Violation” License Plate Numbers

However, if payment for a license plate number is not received at thekiosk or validated by an external entity prior to expiration of a graceperiod timer associated with the license plate number, the system canupdate the data log to indicate that the license plate number is“in-violation,” as shown in FIG. 2B.

10. Parking Enforcement

One variation of the method S100 shown in FIGS. 2A and 3 furtherincludes: accessing an image feed captured by a mobile camera arrangedon the mobile enforcement unit while the mobile enforcement unit movespast vehicles occupying parking spaces in the parking structure in BlockS162; scanning images in the image feed for license plate numbers inBlock S164; in response to detecting a license plate number in an imagein the image feed querying the data log for a status of the licenseplate number in Block S140; and outputting a notification—indicatingabsence of parking validation for the license plate number within agrace period duration following entry of the vehicle into the parkingstructure—in response to the license plate number labeled asin-violation in the data log in Block S142.

Generally, the system can include or interface with a mobile enforcementunit configured to mount to an enforcement vehicle (e.g., a golf cart)driven by the enforcement personnel or configured to be carried by theenforcement personnel while moving throughout the parking structure.While the enforcement personnel drives or carries the mobile enforcementunit along rows of vehicles in the parking structure, the mobileenforcement unit can: capture images of these vehicles; implementmethods and techniques described above to detect and extract licenseplate numbers from these images; query the data log with these licenseplate numbers to check parking authorization status of these vehicles;and then output an audible and/or visual alert—in real-time—as themobile enforcement unit passes a particular vehicle with a license platenumber flagged as unverified with grace period expired in the data log,thereby prompting the enforcement personnel to issue a parking citationto the particular vehicle. The mobile enforcement unit can thereforeautomatically check the status of vehicles parked in the parkingstructure and automatically alert the enforcement personnel ofviolations in real-time as the mobile enforcement unit moves past thesevehicles, thereby enabling the enforcement personnel to avoid manualchecking of individual vehicles and instead enable the enforcementpersonnel to seamlessly monitor the parking structure and quickly issueparking citations for violating vehicles. For example, the mobileenforcement unit can include: a tablet computer containing a camera, aprocessor, a wireless communication module, and an audio speaker; and amount configured to locate the tablet on an enforcement vehicle with thecamera facing outwardly from the right side of the enforcement vehicle.

10.1 Mobile Scanning

In one implementation shown in FIG. 2A, the enforcement personnel maynavigate the enforcement vehicle throughout the parking structure, andthe mobile enforcement unit can concurrently: record a stream of imagesvia the camera; and locally process these images to extract licenseplate numbers depicted in these images, such as according to methods andtechniques described above.

10.2 Vehicle Status Detection

In one implementation shown in FIG. 3, as the mobile enforcement unitdetects each subsequent license plate number in this stream of images,the mobile enforcement unit can transmit a series of queries—to thekiosk or remote computer system via a local ad hoc wireless network orcellular network—for statuses of these license plate numbers stored inthe data log. The kiosk or remote computer system can then return astatus for each license plate number received from the mobileenforcement unit, such as one of: “validated”; “unverified and in graceperiod”; “in-violation” (i.e., unverified with grace period expired); or“citation issued” (e.g., unverified with grace period expired andcitation already issued).

Alternatively, the mobile enforcement unit can store a local copy of thedata log, update the data log responsive to updates received from thekiosk or remote computer system as vehicles are detected entering andexiting the parking structure, and query this local copy of the data logfor license plate number statuses. Yet alternatively, the kiosk orremote computer system can transmit license plate numbers of“in-violation” vehicles to the mobile enforcement unit as grace periodsassociated with these unverified license plate numbers expire; and themobile enforcement unit can maintain a local in-violation log based onlicense plate numbers received from the kiosk or remote computer system,query this in-violation log with license plate numbers as the mobileenforcement unit detects these license plate numbers, and identify anin-violation vehicle when the in-violation log returns a “true” value.

In these implementations, if wireless connectivity to the kiosk orremote computer system is limited in the parking structure, the mobileenforcement unit can alternatively wirelessly synchronize its local copyof the data log or the local in-violation log with a master data logstored on the kiosk or remote computer system each time the mobileenforcement unit is driven past the kiosk by the enforcement vehicle oreach time wireless connectivity is otherwise established with the kiosk.In this implementation, the mobile enforcement unit can also:synchronize grace period timers for unverified license plate numbers inits local data log or local in-violation log when the enforcementvehicle drives the mobile enforcement unit past the kiosk; monitor thesegrace period timers; and automatically update license plate numbers with“in-violation” flags when their corresponding grace period timersexpire.

10.3 Audible Cues

When the data log (or in-violation log) returns an “in-violation” statusof a license plate number, the mobile enforcement unit can output anaudible alarm to prompt the enforcement personnel to stop theenforcement vehicle and issue a parking citation to the correspondingvehicle.

In one implementation shown in FIG. 3, the mobile enforcement unitoutputs this audible alarm in the form of a continuous audible tonewhile a license plate number with an “in-violation” status falls withina center-third of the field of view of the camera (i.e., is detectedwithin the center-third of a last image captured by the camera), therebyenabling the enforcement personnel to quickly identify the offendingvehicle by looking laterally past the mobile enforcement unit while themobile enforcement unit is outputting the audible tone. In a similarexample, when the data log (or in-violation log) returns an“in-violation” status of a license plate number detected in the field ofview of the camera, the mobile enforcement unit can output anintermittent audible tone at a frequency that varies inversely withdistance of the license plate number detected in a last image capturedby the camera from a lateral center of this image. More specifically,the mobile enforcement unit can output this audible tone at a frequency:that increases as the mobile enforcement unit detects the “in-violation”license plate number entering the field of view of the camera andapproaching the lateral center of the field of view of the camera; thepeaks when the mobile enforcement unit detects the “in-violation”license plate number aligned with the lateral center of the field ofview of the camera; and that decreases as the mobile enforcement unitdetects the “in-violation” license plate number moving toward an edge ofthe field of view of the camera as the enforcement vehicle drives pastthe offending vehicle, thereby enabling the enforcement personnel toquickly identify the offending vehicle based on lateral alignment of themobile enforcement unit to the offending vehicle when the frequency ofthe audible tone peaks.

In the foregoing implementation, the mobile enforcement unit canimplement similar methods and techniques to identify an unverifiedlicense plate number that is currently in grace period and to output adifferent audible alarm to preemptively inform the enforcement personnelof a possible future parking violation. While the enforcement personnelmay not stop to issue a citation to this vehicle, the enforcementpersonnel may take mental note of a possible future parking violation bythis vehicle and prioritize rescanning this same vehicle during a futureroute through this parking structure in order to confirm whether parkinghas been validated for this vehicle.

In another implementation, the mobile enforcement unit can detect alicense plate number in an image captured by the mobile enforcement unitand retrieve a status of this license plate number from the data log asthe mobile enforcement unit moves past a vehicle carrying this licenseplate number. Then, in Block S142, the mobile enforcement unit can:output a first audible notification—indicating an in-violation status ofthe license plate number—in response to the license plate number labeledas in-violation in the data log; output a second audiblenotification—different from the first audible notification andrepresenting confirmation of parking validation for the license platenumber—in response to the license plate number labeled as validated inthe data log; or output a third audible notification—different from thefirst and second audible notifications and indicating that the licenseplate number is currently unverified (i.e., currently in a graceperiod)—in response to the license plate number labeled as unverified inthe data log in (near) real-time as the mobile enforcement unit passesthis license plate number. In this implementation, in response tofailure to read a license plate number—with at least a minimumconfidence—in a contiguous sequence of images captured by the mobileenforcement unit, the mobile enforcement unit can outputting a fourthaudible notification—different from the first, second, and third audiblenotifications—in order to prompt the enforcement personnel to reversethe enforcement vehicle and rescan this license plate number.

In the foregoing implementation, the mobile enforcement unit can alsorender—on an integrated or connected display—textual or graphicalnotifications corresponding to these audible notifications. For example,the mobile enforcement unit can render: a live feed of license platenumbers detected in an image feed captured by the mobile enforcementunit camera; and a detection confidence score, a detection time, and astatus of each of these license plate numbers. In this example, themobile enforcement unit can also: highlight—in this live feed—eachdetected license plate number with an in-violation status; and render aprompt to confirm generation of a parking citation for each of thesein-violation license plate numbers.

However, the mobile enforcement unit can communicate statuses of licenseplate numbers—passed by the mobile enforcement unit—in real-time to theenforcement personnel through any other audible, visual, and/or hapticnotifications. Thus, upon perceiving these audible, visual, and/orhaptic notifications, the enforcement personnel may quickly elect tostop the enforcement vehicle in order to place a citation on anin-violation vehicle, mentally log a location of an unverified vehicle,or continue to drive the enforcement vehicle forward (i.e., withoutstopping) to scan a license plate number on a next vehicle in theparking structure.

10.4 Citation Support

Therefore, when the enforcement personnel hears an audible alarmindicating that an “in-violation” license plate number is nearby, theenforcement personnel may stop the enforcement vehicle, view the displayon or coupled to the mobile enforcement unit to verify the in-violationlicense plate number, and then exit the enforcement vehicle to issue aparking citation to the offending vehicle. The enforcement personnel mayalso select the in-violation license plate number on the display inorder to clear the alarm and to indicate that a parking citation hasbeen issued to the offending vehicle. Responsive to this input from theenforcement personnel, the mobile enforcement unit can returnverification of the issued citation to the kiosk or remote computersystem; and the kiosk or remote computer system can then update the datalog accordingly to reflect issuance of a citation to the license platenumber (e.g., by marking the license plate number as “citation issued”in the data log). Alternatively, mobile enforcement unit can update itslocal copy of the data log or the local in-violation log responsive toconfirmation from the enforcement personnel that the citation has beenissued; and the mobile enforcement unit can later wirelessly synchronizeits local copy of the data log or the local in-violation log to themaster data log stored on the kiosk or remote computer system when themobile enforcement unit is again driven past the kiosk by theenforcement vehicle.

In one variation, the mobile enforcement unit includes or is coupled toa printer arranged in the enforcement vehicle. In this variation, themobile enforcement unit can: automatically populate a digital copy of acitation with the in-violation license plate number, an identifier ofthe parking structure (and the location or parking space numbercurrently occupied by the vehicle), the entry time of the vehicle, andthe current time; and then queue the printer to print this citation, asshown in FIG. 3. The enforcement personnel may then place this printedcitation on the corresponding vehicle. For example, the mobileenforcement unit can automatically print a citation via the connectedprinter: when the mobile enforcement unit detects this “in-violation”license plate number in the field of view of the camera; when theenforcement vehicle has stopped soon after the mobile enforcement unitissues an audible alarm for the “in-violation” license plate number(e.g., as detected based on outputs of an IMU integrated into the mobileenforcement unit that indicates that the enforcement vehicle hasstopped); and/or when the enforcement personnel manually confirms theparking citation via the display.

10.5 Citation Confirmation

In one variation shown in FIG. 3, upon detecting an in-violation licenseplate number on a nearby vehicle, the mobile enforcement unit promptsthe enforcement personnel to either confirm issuance of the citation orto cancel the citation, such as by rendering an “issue” option and a“cancel” option on its integrated or connected display. Then, inresponse to the enforcement personnel confirming the citation for thein-violation vehicle, the mobile enforcement unit can: queue the printerto print a paper citation for this vehicle; and re-label the licenseplate number as “citation issued” in the data log. Conversely, inresponse to the enforcement personnel declining the citation for thefirst vehicle, the mobile enforcement unit can: prompt the operator tosupply a reason for declining the citation for the first vehicle;generate a review file containing the enforcement personnel identifier,the enforcement personnel's reason for canceling the citation, thein-violation license plate number, and an image of the correspondingvehicle; upload the review file to a remote database; and re-label thelicense plate number as “citation canceled” in the data log. The systemcan then schedule the review file for review by a supervisor and servethis review file to a supervisor portal, such as within a web browser ornative application; the supervisor may then confirm cancelation of thecitation or discipline the enforcement personnel for improperlycanceling the citation. The system can implement similar methods andtechniques to generate a review file and to schedule evaluation of thereview file if the enforcement personnel fails to either confirm orcancel the citation.

Therefore, in this variation, the system can reinforce compliance by theenforcement personnel by automatically scheduling review of enforcementpersonnel actions (and inaction) that conflict with enforcement rulesdefined for the parking structure.

10.6 License Plate Number Map

In one variation shown in FIG. 3, the system (e.g., the mobileenforcement unit) can populate a map or other representation of theparking structure with locations (e.g., parking space numbers) oflicense plate numbers last detected in images captured by the mobileenforcement unit.

For example, the mobile enforcement unit can record or estimate itslocation within the parking structure over time: based on outputs of ageospatial position sensor integrated into the mobile enforcement unit;by implementing simultaneous localization and mapping techniques; and/orby detecting optical fiducials arranged throughout the parking structurein images captured by the mobile enforcement unit. In this example, upondetecting a license plate number in an image captured by the mobileenforcement unit, the system (e.g., the mobile enforcement unit, thekiosk) can: query a map of the parking structure for a parking structureidentifier, parking structure level, parking row, and/or particularparking space number proximal the location of the mobile enforcementunit at the time the license plate number was detected; and store thisparking structure identifier, parking structure level, parking row,and/or or particular parking space number—which represents the lastdetected location of the license plate number—with this license platenumber in the data log.

In another example, the mobile enforcement unit can capture an image andscan the image for a license plate number, as described above. Inresponse to detecting a license plate number in this image, the mobileenforcement unit can: scan a region of the image below the detectedlicense plate number for a parking space number; and store this parkingspace number—which represents the last detected location of the licenseplate number—with this license plate number in the data log.

In the foregoing examples, the system can also maintain a map (or list,etc.) of parking spaces in the parking structure and annotate the map toindicate occupied and unoccupied parking spaces. Furthermore, when thesystem detects this license plate number in an image captured by theexit camera unit or detects absence of a license plate number in asubsequent image of this parking space, the system can update the map ofthe parking structure to indicate that the parking space last occupiedby this license plate number is now unoccupied.

However, the system can implement any other method or technique todetect and store locations of license plate numbers throughout theparking structure.

10.7 Towing Support

In another variation shown in FIG. 3, the system automatically schedulestowing for an in-violation vehicle, such as if the license plate numbercarried by this vehicle is associated with more than a threshold numberof parking citations (e.g., three unpaid parking citations, includingthe parking citation recently issued to the vehicle).

In one implementation, the mobile enforcement unit scans images—in animage feed captured by its integrated camera—for license plate numbers,as described above. In response to detecting a license plate number inthis image feed, the mobile enforcement unit retrieves both a status ofthe license plate number and a quantity of outstanding parking citationsissued to the license plate number from the data log. If the quantity ofoutstanding parking citations issued to this license plate numberexceeds a threshold quantity defined for this parking structure, thesystem can: implement methods and techniques described above to accessor estimate a current location of the mobile enforcement unit in theparking structure (e.g., the parking structure, the parking structurelevel, and the parking row); or identify a particular parking spacenumber occupied by the in-violation vehicle. The system can then:generate a tow request to tow the vehicle carrying this license platenumber proximal the current location of the mobile enforcement unit inthe parking structure or occupying the particular space number in theparking structure; and then serve this tow request to a towing service.For example, the system can transmit this tow request to the towingservice in the form of an email, a SMS text message, or a robo-call.

Alternatively, the mobile enforcement unit can support the enforcementpersonnel in manually requesting towing from the towing service. Forexample, the mobile enforcement unit can retrieve and display: itslocation or the particular parking space number occupied by thein-violation vehicle; the license plate number of the in-violationvehicle; a phone number for the towing service; and a prompt to call thetowing service to request towing of this vehicle.

Therefore, by detecting or estimating the location of an in-violationvehicle in the parking structure and tracking a quantity of outstandingcitations issued to this vehicle, the system can support towing ofin-violation vehicles according to parking and enforcement rules for theparking structure with limited input or effort from the enforcementpersonnel.

10.8 Multiple Mobile Enforcement Units

In yet another variation, a second mobile enforcement unit is arrangedon the enforcement vehicle with the field of view of its camera facingoutwardly from the left side of the enforcement vehicle. The (first)mobile enforcement unit and the second mobile enforcement unit can thussimultaneously execute the foregoing methods and techniques to detectand indicate “in-violation” vehicles on both the left and right sides ofthe enforcement vehicle as the enforcement personnel drives theenforcement vehicle through the parking structure.

10.9 Selective/Targeted Mobile Enforcement Unit Deployment

In one variation shown in FIG. 2A, the system selectively deploys theenforcement personnel—including the mobile enforcement unit and theenforcement vehicle—to scan a particular parking structure, level in theparking structure, row in the parking structure, or a particular parkingspace in the parking structure based on the status of vehicles thatentered but have not exited the parking structure.

In one implementation, the system monitors a quantity of license platenumbers: of vehicles that entered but have not yet exited the parkingstructure; and labeled as in-violation in the data log. When thequantity of in-violation license plate numbers on vehicles in thisparking structure is below a threshold quantity defined for this parkingstructure, the mobile enforcement unit can prompt the enforcementpersonnel to park the enforcement vehicle in a holding area, such as:near a kiosk in the parking structure in order to assist users parkingin this parking structure; and/or in a recharging booth in order torecharge the enforcement vehicle. However, when quantity of licenseplate numbers labeled as in-violation in the parking structure exceeds athreshold quantity, the system can automatically dispatch theenforcement personnel to this parking structure to scan license platenumbers of vehicles occupying the parking structure. For example, asgrace period times for license plate numbers that recently entered theparking structure expire prior to validation or receipt of payment, thesystem can update the data log to reflect transition from unverified toin-violation status of these license plate numbers. Then, when thequantity of in-violation license plate numbers in the parking structureexceeds a threshold quantity of four (or 1% of vehicles parked in theparking structure; or 2% of the total quantity of parking spaces in theparking structure), the mobile enforcement unit can display a visualnotification and/or output an audible prompt to scan this parkingstructure.

In the variation described above in which the system stores locations oflicense plate numbers in the parking structure, the system can also:aggregate a list of in-violation license plate numbers (and unverifiedlicense plate numbers with grace period timer soon to expire); retrievelast known locations (e.g., parking structure level and row; or parkingspace number) of each of these in-violation license plate numbers; andsort these license plate numbers by proximity to the entrance of theparking structure or by proximity to the enforcement vehicle. The mobileenforcement unit can then present this list of in-violation licenseplate numbers and their locations in the parking structure with a promptto navigate to and issue citations to these vehicles in the orderpresented.

In a similar implementation in which the enforcement personnel monitorsmultiple parking structures, the system can implement similar methodsand techniques to selectively dispatch the enforcement personnel toparticular parking structures. For example, the system can implementmethods and techniques described above to monitor statuses of vehiclesthat have entered but not yet exited a set of (e.g., four) parkingstructures assigned to a particular enforcement personnel and mobileenforcement unit. When quantities of in-violation license plate numberson vehicles in each of these parking structures remains below thresholdquantities defined for these parking structure, the mobile enforcementunit can prompt the enforcement personnel to park the enforcementvehicle in a holding area, such as near a kiosk in a particular parkingstructure—in this set of parking structures—exhibiting a highest rate ofentering vehicles in order to assist users paying for parking in thisparking structure. However, when the quantity of license plate numbersoccupying a first parking structure in this set and labeled asin-violation exceeds a threshold quantity assigned to the first parkingstructure, the system can dispatch the enforcement personnel to scanthis first parking structure. As the enforcement personnel completes ascan of the first parking structure, the system can: calculatequantities of in-violation license plate numbers in other parkingstructures monitored by the enforcement personnel; rank these parkingstructures by quantities of in-violation license plate numbers containedtherein; and dispatch the enforcement personnel to scan these parkingstructures in order of in-violate license plate number quantity. Oncethe enforcement personnel completes a scan of each of these parkingstructures, the system can prompt the enforcement personnel to return toa holding area, such as to assist users attempting to pay for parking inone of these parking structures and/or to recharge the enforcementvehicle.

Therefore, in this implementation, the system can: schedule theenforcement personnel and the mobile enforcement unit to scan licenseplate numbers of vehicles occupying a first parking structure containinga highest quantity of in-violation vehicles during a first period oftime; and schedule the mobile enforcement unit to scan license platenumbers of vehicles occupying a second parking structure containing alesser quantity of in-violation vehicles at a later time.

However, the system can selectively prompt, queue, or schedule theenforcement personnel and the mobile enforcement unit to scan particularparking spaces, parking rows, parking levels, or parking structuresbased on statuses of license plate numbers in a set of parkingstructures and any other schema.

10.10 Parking Space Sensor

In one variation, the system includes or interfaces with parking spacesensors installed over, on, or under parking spaces in the parkingstructure. For example, the parking structure can be outfitted with aninduction-sensing, wireless-enabled parking space sensor installed (or“buried”) under the surface of a parking space or adhered or fastened tothe surface of the parking space. In this example, the parking spacesensor can wirelessly broadcast a status of this parking space—such as“occupied” or “open” in response to the status of the parking spacechanging—directly to the kiosk or to a remote computer system. However,the parking structure can be outfitted with induction-, load-, motion-,or image-based parking space sensors in any other way. The system canthus monitor statuses of parking spaces throughout the parking structurebased on statutes broadcast by these parking space sensors.

In one implementation, the system can predict one or a small subset ofparking spaces in the parking structure that a vehicle recently enteredbased on: the vehicle's entry time into the parking structure; timesthat statuses of parking space sensors in the parking structure changedfrom “open” to “occupied” after this entry time; known locations ofparking spaces assigned to these parking space sensors; and/or distancesfrom the entrance of the parking structure to these parking spaces. Forexample, the system can aggregate a list of parking spaces (e.g., a listof parking space numbers) paired with parking space sensors that changedstate from “open” to “occupied” during a period of ten minutes followingthe vehicle's time of entry into the parking structure. In this example,the system can further filter or rank this list of parking spaces basedon distance from the entrance of the parking structure, such as: byranking these parking spaces by proximity to the parking structureentrance (e.g., based on an expectation that drivers will elect thefirst viable parking space available); and/or by ranking these parkingspaces by proximity to the kiosk, an elevator, or a stairwell (e.g.,based on an expectation that drivers will elect most-convenient parkingspaces).

In this implementation, if this vehicle remains unverified uponconclusion of the grace period following its entry time at the parkingstructure, the system can deploy the mobile enforcement unit to theparking structure with a prompt to specifically scan this subset ofparking spaces that are most likely occupied by this vehicle, therebyenabling the mobile enforcement unit to rapidly find the vehicle andissue a citation. For example, the system can populate a map of theparking structure with locations of parking spaces predicted to containthe vehicle and return this annotated map to the mobile enforcement unitor to the employment personnel directly. In another example, the systemcan generate a list of parking space numbers of spaces predicted tocontain the vehicle and return this list of parking space numbers to themobile enforcement unit or to the employment personal directly.

Therefore, by monitoring status changes of parking spaces throughout thestructure, the system can: predict particular locations likely occupiedby an unverified vehicle in the parking structure; and deploy or promptthe mobile enforcement unit to specifically search for this unverifiedvehicle in these particular locations.

11. Onsite Citation Forgiveness

In another variation shown in FIG. 3, the system can enable a user toremit payment for parking and/or for a citation following receipt of aparking citation.

In one implementation, the kiosk: accesses a list of license platenumbers labeled as “citation issued” in the data log; retrievesquantities of outstanding citations to each of these citation-issuedlicense plate numbers; and filters this list of license plate numbers toinclude only those citation-issued license plate numbers with fewer thana threshold quantity of (e.g., two) outstanding (i.e., unpaid)citations. The kiosk then: displays this filtered list ofcitation-issued license plate numbers, a list of in-violation licenseplate numbers, and unverified license plate numbers (and/or images ofvehicles carrying these license plate numbers); and enables users toselect from these displayed license plate numbers. Thus, if a userselects an unverified or in-violation license plate number at the kiosk,the system can execute methods and techniques described above to:initiate payment (or a payment hold) for parking via a payment methodsubmitted by this user; and re-label this license plate number asvalidated in the data log. (The system can also add a surcharge for latepayment responsive to selection of an in-violation license platenumber.) Similarly, if the user selects a citation-issued license platenumber, the system can: retrieve a current citation fee for eachoutstanding parking citation issued to this license plate number; promptthe user to confirm payment of each citation fee; initiate payment foreach confirmed citation fee via a payment method submitted by this user;re-label the license plate number as validated or “citation paid” in thedata log; and clear each parking citation—linked to this license platenumber—thus paid by the user.

In another implementation, the kiosk can: receive an identifier of acitation issued to a vehicle (e.g., a citation number printed on thecitation, a license plate number of the vehicle) entered by a user; andretrieve a quantity of citations issued to this license plate numberbased on the identifier. Then, if the quantity of citations issued tothis license plate number is less than a threshold quantity specifiedfor the parking structure (or if a vehicle carrying this license platenumber was not previously identified in the parking structure), thekiosk can: forgive the citation and cancel the citation accordingly;enable submission of a payment method at the physical kiosk; andinitiate payment (e.g., a payment hold) for the vehicle parking in theparking structure with the payment method accordingly. Conversely, ifthe quantity of citations issued to this license plate number is greaterthan the threshold quantity specified for the parking structure, thekiosk can indicate that the citation is maintained and prompt the userto submit payment for any outstanding citations, as described above.

Therefore, in this implementation, the system can: cancel citations andenable retroactive payment for parking in the parking structure forlicense plate numbers with few or new outstanding citations, which maycorrelate with users who are not familiar with payment rules in theparking structure; but preserve citations issued to repeat offenders.

12. Exiting Vehicle

As described above and as shown in FIG. 2D, the system can also detectlicense plate numbers in images captured by an exit camera unitinstalled in the parking structure and can store exit times of theselicense plate numbers. In one implementation, upon detecting a licenseplate number in an image captured by the exit camera unit, the systemqueries the data log for the entry time and status of the license platenumber. If the data log returns a validated status for the license platenumber, the system can: calculate a time difference between the entrytime and the exit time of the license plate number; implement a parkingfee model to transform this time difference into a final parking costfor the license plate number; calculate a cost difference between thisfinal parking cost and a fee charged to the associated payment methodfor this parking period; and issue a refund for this cost difference tothe associated payment method.

For example, in response to detecting the a license plate number in animage captured by the exit camera unit, the system can: label thislicense plate number as “exited” in the data log in Block S150;calculating a parking fee for the license plate number based on a timedifference between its entry time and exit time; and credit anoverpayment to a payment method linked to the license plate number basedon a monetary difference between this parking fee and a payment holdpreviously initiated to this payment method.

Finally, the system can clear the license plate number from the data logsuch that the data log contains license plate numbers of vehiclescurrently occupying the parking structure.

12. Street Parking

In another variation, the system can execute Blocks of the method tomonitor and support parking enforcement for on-street parking. Forexample, the system can include or interface: with underground vehiclesensors to detect vehicles entering and exiting on-street parkingspaces; and/or with pole- or building mounted cameras to detect vehiclesentering and exiting on-street parking spaces and to read license platenumbers of these vehicles. In this variation, the system can alsointerface with parking meters or on-street parking kiosks to presentlicense plate numbers recently detected on parked vehicles and toreceive payment methods—in association with these parking spaces and/orlicense plate numbers—from users. The system can then interface with themobile enforcement unit, as described above: to detect license platenumbers on parked vehicles occupying on-street parking spaces; toretrieve statuses of these license plate numbers; and to selectivelyprompt the enforcement personnel to selectively issue parking citationsto in-violation vehicles occupying these parking spaces.

For example, in the implementation described above in which the systemsupports an enforcement personnel and mobile enforcement unit inmonitoring multiple parking structures, the system can execute theforegoing methods and techniques to monitor statuses of vehiclesoccupying on-street parking spaces between and/or near these parkingstructures. In this example, the enforcement personnel and the mobileenforcement unit can thus monitor and enforce parking rules both acrossmultiple parking structure and on-street parking spaces concurrently.

The systems and methods described herein can be embodied and/orimplemented at least in part as a machine configured to receive acomputer-readable medium storing computer-readable instructions. Theinstructions can be executed by computer-executable componentsintegrated with the application, applet, host, server, network, website,communication service, communication interface,hardware/firmware/software elements of a user computer or mobile device,wristband, smartphone, or any suitable combination thereof. Othersystems and methods of the embodiment can be embodied and/or implementedat least in part as a machine configured to receive a computer-readablemedium storing computer-readable instructions. The instructions can beexecuted by computer-executable components integrated bycomputer-executable components integrated with apparatuses and networksof the type described above. The computer-readable medium can be storedon any suitable computer readable media such as RAMs, ROMs, flashmemory, EEPROMs, optical devices (CD or DVD), hard drives, floppydrives, or any suitable device. The computer-executable component can bea processor but any suitable dedicated hardware device can(alternatively or additionally) execute the instructions.

As a person skilled in the art will recognize from the previous detaileddescription and from the figures and claims, modifications and changescan be made to the embodiments of the invention without departing fromthe scope of this invention as defined in the following claims.

I claim:
 1. A method for managing parking within a parking area comprising: in response to detecting a first license plate number in a first image captured by an entry camera unit arranged near an entry of the parking area, querying a whitelist for the first license plate number; in response to the whitelist excluding the first license plate number: labeling the first license plate number as unverified in a data log associated with the parking area; initiating a timer, associated with the first license plate number, for a duration of a grace period; and in response to expiration of the timer prior to validation of the first license plate number, relabeling the first license plate number as in-violation in the data log; in response to detecting the first license plate number in a second image captured by a mobile enforcement unit moving through the parking area, querying the data log for a status of the first license plate number; in response to the first license plate number labeled as in-violation in the data log, serving a prompt to an enforcement personnel associated with the mobile enforcement unit to issue a citation to a first vehicle carrying the first license plate number; and in response to detecting the first license plate number in a third image captured by an exit camera unit arranged near an exit of the parking area, labeling the first license plate number as exited in the data log.
 2. The method of claim 1, further comprising, in response to a quantity of license plate numbers labeled as in-violation in the data log exceeding a threshold quantity, dispatching the mobile enforcement unit to the parking area to scan license plate numbers of vehicles occupying the parking area.
 3. The method of claim 1, further comprising: in response to detecting a second license plate number in a third image captured by a second entry camera unit arranged near a second entry of a second parking area, querying a second whitelist for the second license plate number; in response to the second whitelist excluding the second license plate number: labeling the second license plate number as unverified in a second data log associated with the second parking area; initiating a second timer, associated with the second license plate number, for the duration of the grace period; and in response to expiration of the second timer prior to validation of the second license plate number, relabeling the second license plate number as in-violation in the second data log; and in response to a first quantity of license plate numbers labeled as in-violation in the data log associated with the parking area exceeding a second quantity of license plate numbers labeled as in-violation in the second data log associated with the second parking area: scheduling the mobile enforcement unit to scan license plate numbers of vehicles occupying the parking area during a first period of time; and scheduling the mobile enforcement unit to scan license plate numbers of vehicles occupying the second parking area during a second period of time succeeding the first period of time.
 4. The method of claim 1, further comprising: in response to detecting a second license plate number in a third image captured by the entry camera unit, querying the whitelist for the second license plate number; and in response to the whitelist containing the second license plate number: initiating payment for parking in the parking area via a stored payment method associated with the second license plate number; and labeling the second license plate number as validated in the data log.
 5. The method of claim 1, further comprising: in response to detecting a second license plate number in a third image captured by the entry camera unit at a first time, querying the whitelist for the second license plate number; and in response to the whitelist excluding the second license plate number: labeling the second license plate number as unverified in the data log associated with the parking area; and initiating a second timer, associated with the second license plate number, for the duration of the grace period; in response to receiving identification of the second license plate number and submission of a second payment method through a physical kiosk associated with the parking area prior to expiration of the second timer: relabeling the second license plate number as validated in the data log; and initiating a payment hold, for a maximum daily parking rate in the parking area, from the second payment method; and in response to detecting the second license plate number in a fourth image captured by the exit camera unit at a second time: labeling the second license plate number as exited in the data log; calculating a parking fee for the second license plate number based on a time difference between the first time and the second time; and crediting an overpayment to the second payment method based on a monetary difference between the parking fee and the payment hold.
 6. The method of claim 5, further comprising: aggregating a list of license plate numbers labeled as unverified in the data log, the list of license plate numbers comprising the second license plate number; aggregating a set of images captured by the entry camera, each image in the set of image depicting a license plate number in the set of license plate numbers; presenting the list of license plate numbers through the physical kiosk; and receiving identification of the second license plate number in the form of selection of an image depicting the second license plate number, from the set of images, at the physical kiosk.
 7. The method of claim 1, further comprising: in response to detecting a second license plate number in a third image captured by the entry camera unit at a first time, querying the whitelist for the second license plate number; and in response to the whitelist excluding the second license plate number, labeling the second license plate number as unverified in the data log; and aggregating a list of license plate numbers labeled as unverified in the data log, the list of license plate numbers comprising the second license plate number; ordering the license plate numbers, in the list of license plate numbers, according to timestamps of images captured by the entry camera and depicting license plate numbers in the list of license plate numbers; presenting the list of license plate numbers through a physical kiosk associated with the parking area; via the physical kiosk: receiving selection of the second license plate number from the list of license plate numbers; and receiving submission of a second payment method associated with the second license plate number; and in response to receiving identification of the second license plate number and submission of the second payment method via the physical kiosk: initiating payment for parking in the parking area, by a second vehicle carrying the second license plate number, via the second payment method; and labeling the second license plate number as validated in the data log.
 8. The method of claim 1, further comprising: in response to detecting a second license plate number in a third image captured by the entry camera unit at a first time period, querying the whitelist for the second license plate number; and in response to the whitelist excluding the second license plate number, labeling the second license plate number as unverified in the data log; and aggregating a list of license plate numbers labeled as unverified in the data log, the list of license plate numbers comprising the second license plate number; presenting the list of license plate numbers through a physical kiosk associated with the parking area; via the physical kiosk: receiving selection of the second license plate number from the list of license plate numbers; receiving submission of a second payment method associated with the second license plate number; and prompting confirmation of a link between the second payment method and the second license plate number for future parking in the parking area; in response to receiving identification of the second license plate number and submission of the second payment method via the physical kiosk: initiating payment for parking in the parking area, by a second vehicle carrying the second license plate number, via the second payment method; and labeling the second license plate number as validated in the data log; and in response to confirmation of the link between the second payment method and the second license plate number for future parking in the parking area, storing the second payment method in association with the second license plate number.
 9. The method of claim 1, further comprising: accessing an image feed captured by a mobile camera arranged on the mobile enforcement unit while the mobile enforcement unit moves past vehicles occupying parking spaces in the parking area; scanning images in the image feed for license plate numbers; and in response to detecting a license plate number in an image in the image feed: querying the data log for a status of the license plate number; in response to the license plate number labeled as verified in the data log, outputting a first audible notification to the enforcement personnel occupying the mobile enforcement unit; and in response to the license plate number labeled as in-violation in the data log, outputting a second audible notification, different from the first audible notification, to the enforcement personnel.
 10. The method of claim 9, further comprising: in response to detecting a license plate number in the image and in response to the license plate number labeled as un-verified in the data log, outputting a third audible notification, different from the first audible notification and the second audible notification, to the enforcement personnel; and in response to failure to read a license plate number in a contiguous sequence of images in the image feed, outputting a fourth audible notification, different from the first audible notification, the second audible notification, and the third audible notification, to prompt the enforcement personnel to rescan the license plate number.
 11. method of claim 1, further comprising: accessing an image feed captured by a mobile camera arranged on the mobile enforcement unit while the mobile enforcement unit moves past vehicles occupying parking spaces in the parking area; scanning images in the image feed for license plate numbers; and detecting the first license plate number in the second image in the image feed; in response to the enforcement personnel confirming the citation for the first vehicle carrying the first license plate number, queuing a printer in the mobile enforcement unit to print a paper citation specifying the first license plate number; and in response to the enforcement personnel declining the citation for the first vehicle: prompting the operator to supply a reason for declining the citation for the first vehicle; and scheduling the reason for review by a supervisor.
 12. The method of claim 1, further comprising: accessing an image feed captured by a mobile camera arranged on the mobile enforcement unit while the mobile enforcement unit moves past vehicles occupying parking spaces in the parking area; scanning images in the image feed for license plate numbers; and in response to detecting the first license plate number in the second image in the image feed, retrieving a quantity of outstanding parking citations issued to the first license plate number; and in response to the quantity of outstanding parking citations issued to the first license plate number exceeding a threshold quantity: accessing a current location of the mobile enforcement unit in the parking area; generating a tow request to tow the first vehicle carrying the first license plate number proximal the current location of the mobile enforcement unit in the parking area; and serving the tow request to a towing service.
 13. The method of claim 1, further comprising: receiving an identifier of the citation issued to the first vehicle at a physical kiosk associated with the parking area; accessing a quantity of citations issued to the first license plate number based on the identifier; and in response to the quantity of citations issued to the first license plate number falling below a threshold quantity: enabling submission of a payment method at the physical kiosk; initiating payment for the first vehicle parking in the parking area with the payment method; and canceling the citation.
 14. The method of claim 1: further comprising, in response to detecting the first license plate number in the first image, querying a pre-validation list for the first license plate number, the pre-validation list comprising a list of license plate numbers designated in pre-validation requests submitted by an external entity; wherein labeling the first license plate number as unverified in the data log comprises labeling the first license plate number as unverified in the data log further in response to the pre-validation list excluding the first license plate number; and further comprising: in response to detecting a second license plate number in a third image captured by the entry camera unit, querying the pre-validation list for the second license plate number; and in response to the pre-validation list containing the second license plate number, labeling the second license plate number as validated in the data log.
 15. The method of claim 14, further comprising: in response to the pre-validation list containing the second license plate number, initiating a validation timer for a maximum validation duration specified by the external entity; and in response to absence of the second license plate number from an image captured by the exit camera and in response to absence of entry of an alternate payment method for the second license plate number prior to expiration of the validation timer: initiating payment from the external entity on behalf of the second vehicle for the maximum validation duration; and relabeling the second license plate number as unverified in the data log.
 16. A method for managing parking within a parking area comprising: in response to detecting a license plate number in a first image, captured by an entry camera unit arranged near an entry of the parking area at a first time, querying a whitelist for the first license plate number; in response to the whitelist excluding the first license plate number: appending the data log for the parking area with the first license plate number labeled as unverified; and in response to absence of submission of a new payment method, in association with the first license plate number, at a physical kiosk in the parking area prior to a second time succeeding the first time by a grace period duration, relabeling the first license plate number as in-violation in the data log; in response to detecting the first license plate number in a second image captured by a mobile enforcement unit moving through the parking area and associated with an enforcement personnel: querying the data log for a status of the first license plate number; and in response to the first license plate number labeled as in-violation in the data log, serving a prompt to the enforcement personnel to issue a citation to a vehicle carrying the first license plate number; and in response to detecting the first license plate number in a third image captured by an exit camera unit arranged near an exit of the parking area at a third time, labeling the first license plate number as exited in the data log.
 17. The method of claim 16, further comprising: in response to the whitelist containing the first license plate number: initiating payment for parking in the parking area via a stored payment method associated with the first license plate; and labeling the first license plate number as validated in a data log associated with the parking area; and in response to the whitelist excluding the first license plate number, in response to submission of the new payment method, in association with the first license plate number, at the physical kiosk prior to the second time, relabeling the first license plate number as validated in the data log.
 18. A method for managing parking within a parking area comprising: deploying a mobile enforcement unit to the parking area; accessing an image feed captured by a mobile camera arranged on the mobile enforcement unit while the mobile enforcement unit moves past vehicles occupying parking spaces in the parking area; scanning images, in the image feed, for license plate numbers; and for each license plate number detected in the image feed: querying a data log associated with the parking area for a status of the license plate number; and in response to the license plate number labeled as in-violation in the data log: outputting a first notification to an enforcement personnel occupying the mobile enforcement unit as the mobile enforcement unit moves past a vehicle carrying the license plate number, the first notification representing absence of parking validation for the license plate number within a grace period duration following entry of the vehicle into the parking area; and queuing a printer to print a paper parking citation designating the license plate number.
 19. The method of claim 18, further comprising, for each license plate number detected in the image feed: in response to the license plate number labeled as validated in the data log, outputting a second notification to the enforcement personnel as the mobile enforcement unit moves past a vehicle carrying the license plate number, the second notification different from the first notification and representing confirmation of parking validation for the license plate number; and in response to the license plate number labeled as un-validated in the data log, outputting a third notification to the enforcement personnel as the mobile enforcement unit moves past a vehicle carrying the license plate number, the third notification different from the first notification, representing absence of parking validation for the license plate number, and representing presence of the vehicle in the parking area for less than the grace period duration.
 20. The method of claim 18, further comprising: in response to detecting a first license plate number in a first image captured by an entry camera unit arranged near an entry of the parking area, querying a whitelist for the first license plate number; in response to the whitelist containing the first license plate number: initiating payment for parking in the parking area via a stored payment method associated with the first license plate; and labeling the first license plate number as validated in a data log associated with the parking area; in response to the whitelist excluding the first license plate number: appending the data log for the parking area with the first license plate number labeled as unverified; initiating a timer, associated with the first license plate number, for a duration of a grace period; in response to submission of a new payment method, in association with the first license plate number, at a physical kiosk in the parking area, relabeling the first license plate number as validated in the data log; in response to expiration of the timer prior to validation of the first license plate number, relabeling the first license plate number as in-violation in the data log. 